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What Ancestry Tests Can Say About Your Health

You’ve seen the commercials on TV:

An ordinary man looks into the camera and tells us that he was certain his family’s roots were from Italy. Turns out, his DNA has something else to say about that. Actually, his ancestors were mostly from Germany, with only a pasta’s bit of his genes from Italy. Who knew? Maybe that’s why he likes schnitzel, and he’s not so hot for tiramisu.

I made up that precise scenario, but it’s a close rendering. What’s totally true is that Mr. Ordinary Guy uncovered the secret of his family origins by having his DNA—the composite of all of our genes—analyzed by a company called AncestryDNA. It’s one of about a dozen companies that are using relatively new DNA sequencing technology to scan an individual’s entire genome (all the genes contained in DNA) to identify their geographical heritage, potential for developing a handful of illnesses, and even a dive into their personality or physical traits. Do you feel like you constantly need 8 hours of sleep, otherwise you’re useless? 23 & Me, an Ancestry competitor, can likely tell you it’s your DNA’s fault, and not that you are, as you may have thought, just a sloth. Gentleman, do you worry that you’ll lose your hair? Worry no more. 23 & Me will explain whether you can relax, or whether your DNA provides just one more reason to stress out about your future. The company’s gene-testing software can even tell you your earwax type. And, of course, we know that’s important.

From Ancestry, at least, all it costs is $79 (down from $99 last year) and a bit of your saliva shipped off (in a prepaid mailer) to the company. In six to eight weeks, Voila! Your inherited mix of family pedigrees is a mystery no more.

I say, so what?


What it Costs to Know Your DNA

Alas, as in any offer that promises so much for so relatively little—Ancestry’s genetic sleuthing even comes with a free 14-day trial, and despite being all the rage these days, handing over your DNA has a poorly advertised downside that screams “Caveat Emptor.” You can easily join the millions who have disclosed the personal, unique, and private contents of their DNA to what is, in essence, a stranger. But I’m here to tell you that you do so with some risks attached. Most troubling, many of the potential perils aren’t disclosed in the recent barrage of commercials or even in the companies’ websites and consent agreements.

AncestryDNA, the testing division of, says it has scoured the genomes of 10 million people over the past few years.  Its leading competitor, 23 & Me, has studied the DNA of another five million. An industry analyst says the surging genetic detective business will triple to $310 million in 2022 from $99 million last year. On last year’s Black Friday shopping day, 15 million Ancestry tests were ordered (many likely as gifts), according to Gizmodo, the online news site. That’s a whole lot of spit.

Not surprising, the value of our DNA is galloping ahead.  In 2016, Ancestry, a privately owned company, was believed to be worth $2.6 billion. 23 & Me was valued last year at about $1.5 billion. And the companies don’t just vacuum up all of this value from the consumer testing services. Last year, the British pharmaceutical giant Glaxo signed a $300 million deal with 23 & Me. In return, Glaxo gets access to all the DNA 23 & Me’s customers handed over. The drug maker will use the DNA to search for genetic-linked diseases that might provide clues to developing new medicines.

In some cases, the genetic test results can be profound. Adopted children have found their biological parents, and vice versa. Recently on NewsHour, a middle-aged woman author says she found out late in life that her father is indeed not her biological parent. It was startling, to say the least. Turns out he was a sperm donor, and her parents never told her about it. It made her angry, she says. But it also explained a lot that had troubled her. She didn’t look like her parents. More important, she always had this nagging sense that something was amiss. For her part, at least, the knowledge was liberating, though she was angry that her origin had been kept a secret.

That’s an example of the enormous power of unlocking our individual DNA code. And she is far from alone.

Before we go on, let’s take a quick look at the technology driving this quickly growing business. I promise as little biomedical jargon as possible. But I believe it’s worth knowing why these businesses are booming.

The main driver of this new gene age is the ability to sequence the genome, a breakthrough that has revolutionized medical research. While the costs of identifying the complete genetic makeup of an individual is costly, at about $1,000  (one-tenth its cost 10 years ago), the gene-testing companies can do it for far less. That’s because they can produce results by identifying only a tiny portion of one’s DNA.


What Your DNA Tells You

Beware, a little biology lesson around the next curve. One can think of DNA as being a dictionary, and all our genes are the words inside. While English language words are composed of variations of the alphabet’s 26 letters, DNA’s words (or genes) are made up of just four letters. These letters represent four different chemicals, identified most simply as A, T, C, and G.  Individual genes contain these four letters jumbled in differing sequences and stitched together in strings that are each typically 30,000 or so letters long. By using sequencing machines (the heart of the current genetic advances), labs can identify the precise order of the four letters that constitute your DNA. Since scientists have already established the precise arrangement of the letters for many genes, the sequencers can quickly, through a type of search technique used in word processing software, identify the specific makeup of your version of those genes. In this way, the labs can see how the sequence of letters of your genes might compare to others.

This is where it gets slightly more complicated. The specific letter order in your DNA is 99.5% similar to everyone else’s. The 0.5% difference is what makes you unique. This slight genetic variation is passed along to us by our parents, as it was passed to them from generation to generation in the past. The variations are produced by very small differences in the order of the letters that constitute our genes. As I wrote, the testing companies don’t sequence the arrangement of the letters in all of your DNA—that would be too expensive and time-consuming. Instead, they only search for the small, yet important letter variations in your DNA that distinguish who you are, many of your inherited traits, and the potential for genetically-linked illnesses that you inherited from your family. To date, scientists have identified many thousands of these variants among the billion or so letters that comprise the entire human genome.

So, for those just interested in where your relatives came from, scientists have found that generations of people who lived in certain regions of the world share variations of certain letters. For those interested in the health risks contained in our DNA, scientists have linked certain variations to certain genes. One problem arises right off the bat. Only a few very specific gene variations directly cause disease. These variants are often referred to as mutations, though that doesn’t always mean the variants are bad for us.  These same mutations in DNA letter arrangements have been found as the direct cause of inherited disorders like cystic fibrosis or sickle cell disease. The rest of the variants, sometimes also called mutations, don’t always lead to illness, but do so only a percentage of the time.


Is it Worth the Trouble?

This is where interpreting the results of a health-related genetic test can cause trouble. Indeed, the companies all warn, but only in small print, that you should be prepared for information you might not expect and that might cause you some concern.  

Consider Alzheimer’s disease—something we all fear in ourselves or for our relatives. About 20 years ago, researchers identified a few gene variants that can predispose people to getting a late-in-life version of the disease. So, that might help someone who’s losing their memory know if their senility is due to Alzheimer’s. It might be useful in treating the disease, but not that much. More controversial is this: Scientists have found the risk due to the variants is about 80%. That seems high. But if you’re young, how does this knowledge help you? It doesn’t right now, at least not until researchers can find a way to prevent the disease, and they’re far from doing that. And if you’re older, like me, well, do you really need to know? For my part, it would just be one more upsetting thing that I can’t do much to change.

On the other hand, some people want to know. And who am I to judge?

The number of ailments 23 & Me and some of the other companies can detect are still small. At this time, 23 & Me says it can identify your potential risk of developing nine different ailments. These include the late in life onset of Alzheimer’s, Parkinson’s disease, and an inherited form of breast and ovarian cancer. (see the full list below with a link to 23 & Me). 23 & Me’s family origin test costs $99 and $100 more if you want the health-related search, too. In addition, for the $199 fee, 23 & Me and a few of the other companies can also provide what they call a wellness report, and a report that shows whether 25 different physical traits are a result of your genetics. The wellness report can tell you if you’re especially sensitive to alcohol or caffeine, whether you’re likely to become, or someday will be lactose intolerant, and if you’re especially prone to putting on weight from saturated fats, among a list of eight such characteristics. The traits that can be identified include whether you’re especially attractive to mosquitoes (really!), whether you have an aversion to the peppery taste of cilantro (that’s cool, I guess), hair thickness, earwax type (there’s more than one kind?), bald spot, and what time waking up suits you best.

In my mind, the most useful disease predictor is the one that can pick up a mutation that frequently causes an inherited form of breast and ovarian cancer. A positive finding for this variant can cause a great deal of concern. It’s a good thing to know, especially if the cancers are common in your family. But what action should follow? Most experts recommend getting another confirming genetic test from an authorized medical lab, and to consult your doctor. A significant number of women carrying the mutation in their genes, especially after they’ve already had children, consider removing their breasts and ovaries to prevent disease. But what if you’re young and years away from bearing kids?  And neither your doctor, and certainly not a gene testing company, can tell you exactly what your risk is, as the two gene mutations linked to the cancers don’t always lead to disease. Researchers say carrying the mutations increase a woman’s risk of developing breast cancer to between 45% and 65% by about age 70.

Here’s another sticky concern: If your test is positive, it means some number of men and women in your family also carry the same risk.

Along with a list of cautions in the companies’ consent forms, all of them point out that your genetics only play a partial role in leading to an illness. They also say that nobody knows for sure what the other elements are that contribute to disease. Interesting, to be sure.


Risking Your Privacy

The trait aspect might be a good conversation item. Maybe even a fun pick-up line. But there is another concern: your privacy. Some people might not give a hoot about who has access to their DNA. Your DNA, though, is quite possibly the most important part of who you are. The companies say they won’t share your DNA unless you consent to that. If you do, and most customers do, the genetic testing companies typically share (by that, I mean, sell) your information, often pooled together with many others, to drug makers and academic researchers. In fact, there’s a federal law that requires your DNA not be shared with anyone unless you consent. At present, there aren’t any reports of abuse. Still, why take the risk?

I say keep your DNA to yourself, but that’s just my take. Unless, of course, breast or ovarian cancers are common in your family. In that case, it’s best to consult with a doctor. Let’s say you’re positive to one of the mutations. That means your daughter or mother might also be at risk. Even your cousins or aunts. Even very distant cousins you hardly see or know. What then? A specially trained genetics counselor can help you decide your treatment options as well as whether to share the information with others in your family, many of whom will likely by disturbed by the news.

One additional tidbit—AncestryDNA can help you build a family tree without providing your DNA. Its website provides access to several databases, such as marriage or death reports, or census and immigration data. The company can even help you find where your early ancestors lived before they came to the US. You can also search for free on your own through databases like AncestryDNA does make it easier, though.

Of course, now that you know the benefits and risks, only you can best decide whether to let your DNA sit around forever in some companies’ computers. Remember, you always own your DNA, but by providing consent, you provide the genetic testing company a license to share what’s yours with whomever they want. As I said, buyer beware.

For a full list of ailments, wellness characteristics, and traits detected by 23&Me, follow this link here. If you want to check out a sample report, go here.

That’s my offering of insights into the world of DNA testing and ancestry—I hope it helps as you venture into your own genetics.


Michael Waldholz is a Pulitzer Prize winning healthcare journalist and author. For many years, he was the chief medical reporter at the Wall Street Journal. While we have a host of health-related subjects we plan to cover in the Healthcare Matters series, please feel free to send any questions you have for the author or our team to, and don’t forget to follow us on FacebookTwitter, and Instagram.


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